Player falling through landscape (4.23)

Hi all

I am working on a first person project based off of the First Person blueprint example - most of my levels run fine but I am having problems with landscape collision.

Collision works fine when in-editor or standalone, but when packaged, the collision seems to have some weird offset - if you try and walk on the ground, you fall through it, but by setting the player spawn well above the landscape I found that the collision is actually offset at least several metres vertically.

I’m not sure what the command is to show player collision in the game, which is making it hard to see what this offset is exactly.

Few details to cover the most obvious causes:

  1. This does not happen with a fresh project
  2. My player character has ‘Pawn’ collision on the capsule component, see screenshot
  3. In editor, the landscape appears to have the correct collision (toggling player collision shows the landscape collision matches the mesh)
  4. All engine settings are default, I haven’t messed around with the physics settings
  5. It works in the editor, so I’m not sure what in my code could possibly be causing it!

Here is a video of it happening: https://streamable.com/89i9n

The command is ShowFlag.Collision 1 make sure it’s development build.
Also try building before packaging.

That shows primitive collision but doesn’t seem to show terrain collision, which I’ve only been able to find by toggling ‘Player Collision’ in the editor view. It does show that my collision capsule is in the right place though (which makes sense, as collision with other static geometry is absolutely fine).

Tried rebuilding, didn’t seem to fix it. Even tried removing all intermediate build stuff from my directory and doing a fresh build and it still doesn’t work.

Quick update on this. I believe the problem is being caused by the FMOD Integration Plugin, as when I remove it from the project, the terrain issue goes away. I have no idea why the FMOD plugin would be interfering with physics components in the engine.

When creating a brand new test project with the FMOD Plugin enabled (but no FMOD content in the project, i.e. no banks built) I get a compile error:

Assertion failed: Local1.IsValid() && !Local1.ContainsNaN() [File:D:/Build/++UE4/Sync/Engine/Source/Runtime/Engine/Private/PhysicsEngine/ConstraintInstance.cpp] [Line: 359]

I have posted on the FMOD forums here: 4.23 Integration Physics / Compile issues - Unreal Engine - FMOD Forums

Solved - for anyone else having the same problem, the FMOD Integration plugin does not compile under VS 2019.

I found an installer for VS 2017, uninstalled 2019, and the game now compiles and runs correctly.